Agents affecting lipid metabolism. XXXI. Properties of an inhibitor of cholesterol synthesis present in rabbit liver mitochondria

Abstract

Aqueous extracts of mitochondria from livers of starved animals have been reported to inhibit hepatic cholesterol synthesis. Some properties of a mitochondrial extract prepared from starved rabbits have been studied. The extract depressed the incorporation of both 2-14C-acetate and 3H-mevalonate into cholesterol by rat liver homogenates, giving concentration–dependent responses. The active factor was unstable to heat, but stable under in vitro incubation conditions, to pH changes, and to storage in the dark and cold. It was cationic and associated with one or more large molecules (mol. wt. 50 000–150 000); it was not cleaved by trypsin digestion. Fractionation experiments did not result in any significant enrichment of inhibitory activity.